1. Field of the Invention
The present invention relates to an inventory management system, etc., which calculates a safety inventory quantity of a product, and performs inventory management based on the calculated safety inventory quantity.
2. Description of the Related Art
Recently, maintaining a suitable inventory quantity becomes important in the sales of products. For example, if the inventory quantity is too large, management costs increase, and conversely, if the inventory quantity is too little, there is a possibility to miss sales opportunity.
In order to maintain a suitable inventory quantity, the market demands of products are sometimes forecasted. This is because it becomes easy to maintain an appropriate inventory quantity if the market demand forecast is accurate. Accordingly, Unexamined Japanese Patent Application KOKAI Publication No. 2007-141036 or the like discloses a technology for forecasting a market demand accurately. According to such a technology, a management computer calculates a tendency function (tendency curve) based on the transition of an actual achievement of an order entry, calculates a rate between the tendency curve and an actual achievement of an order entry, and calculates a time change in the rate. Subsequently, the management computer calculates a periodical function with respect to a time change in a logarithm of the rate by fitting. Next, the management computer converts the periodical function, calculated by fitting, from the logarithm scaling to a normal scaling. Further, the management computer synthesizes a periodical fluctuation model (periodical function) in the acquired normal scaling with a tendency curve (tendency function) to calculate a market demand forecasting curve, thereby forecasting a market demand using the market demand forecasting curve. The use of the management computer enables effective and exact market demand forecasting in consideration of a periodical fluctuation of an error in a market demand forecasting for a predetermined product.
However, even if such market demand forecasting is performed, it is preferable that an inventory quantity should have some margins in order to cope with an unexpected market demand fluctuation. In order to do so, for example, as disclosed in Unexamined Japanese Patent Application KOKAI Publication No. 2004-75321, it is typical to set a safety inventory quantity. According to a technology disclosed in this publication, a management computer calculates a normal inventory reference value based on a certain period deflection width inventory (a product of the total of quantities of products to be sold in a certain period in which a stock quantity is settled and a deflection width rate) and a safety inventory quantity. Note that a deflection width rate is a rate of a deflection width of an actual achievement quantity from a past expected quantity. Next, the management computer calculates an inventory reference value based on the normal inventory reference value and a lumping inventory reference value. Further, the management computer calculates an inventory expected quantity based on a quantity of a product to be sold and an inventory actual achievement expected quantity. Finally, the management computer calculates a replenishment quantity of a product based on the difference between the inventory actual achievement expected quantity and an inventory reference quantity.
However, like the foregoing management computer, if a safety inventory quantity is fixed, there is a possibility that the safety inventory becomes an excessive inventory when a market demand is smaller than a forecast. On the other hand, a safety inventory is for preparing an unexpected fluctuation in a market demand, so that the significance of a safety inventory may be lost if the safety inventory is merely reduced quantitatively.
The present invention has been made in view of the foregoing problems, and it is an object of the present invention to provide an inventory management system which calculates a more appropriate safety inventory quantity, and performs inventory management using the safety inventory quantity, an inventory management method and a computer-readable recording medium.